1. Field of the Invention
The present invention relates to a device comprising an elongated tubular body arranged to be located in water in an essentially vertical position, wherein the tubular body at the bottom comprises an open end and at the top a narrowing portion, which ends in an opening arranged to be located above the level of the surrounding water.
2. Description of the Prior Art
From U.S. Pat. No. 3,064,137 a floatable device is known, which comprises a tube with an internal water level, which is brought to move upwards and downwards in the tube by means of the waves of the surrounding water. Thereby, the air located above the water level in the tube will stream out and in through an opening provided at the top of the tube. In this case, a turbine and a generator are provided to gain power, which is generated by the movement of this air stream.
From U.S. Pat. No. 4,603,551 a buoy is previously known, which moves up and down in a floating elongated structure. By this movement, water is pumped by means of a piston and a cylinder, via valves, into a space, where it drives a water turbine and an electric generator.
The object of the above mentioned devices is to generate energy which may be gained by motions of waves.
Lighthouses comprising a lighting device usually mark out grounds at sea. In order to make these lighthouses effectual, it is required that these lighting devices are provided at such a level that they are not blocked by waves in heavy sea. Such lighthouses must have a sufficient height and be stable in order to withstand rough weather and therefore they are expensive to build.
Such lightening houses must have a sufficient height and be stable in order to withstand rough weather and therefore they are expensive to build.
The object of the present invention is to provide a device which is arranged to force, in an effective way, a water quantity, in the form of, e.g. a water jet, upwards from a water volume and especially in order to be able to mark and draw attention to objects of various kinds. This may be used in many fields of application. One such field is marking of grounds and other objects, which have to be observed at sea.
This object is achieved according to the invention with the initially defined device, which is arranged to establish a water level in the narrowing portion of the tubular body, which is lower than the level of the surrounding water and to level out intermittently this level difference in such a way that the water in the tubular body is transported up to a higher level than the level of the surrounding water by means of the narrowing portion. By a suitable dimensioning of the narrowing portion and its opening such a water jet may be ejected to a considerable height and highly above any existing crest of waves. Thereby, a marked ground may e.g. be visible from a long distance and a lot of time is given for ships to steer away from the ground. By an elongated water jet, the distance to a marking may also be better estimated than in the case that it is marked out by a point-shaped lighting device.
According to a preferred embodiment of the invention, a valve device is provided at the opening of the tubular body, which valve device is arranged to open when a determined overpressure is obtained within the tubular body. Thereby, when a sufficient level difference is established between the water in the tube and the level of the surrounding water, an upwards ejecting water jet is obtained.
According to a preferred embodiment of the invention, such a valve device may also be arranged, in case of subpressure in the tubular body, to allow an inflow of air into the tubular body, If the device with the tubular body is provided to be movable, it may thereby by its movement xe2x80x9cpumpxe2x80x9d up an internal pressure in such a way that said level difference is established. This movement may be generated by the fact that it is arranged to be floating in water, wherein said level difference is established by the fact that it moves essentially upwards and downwards in an essentially vertical direction by means of existing waves At a sufficient height of the waves, a water jet may be ejected essentially once a wave. This will occur by the fact that the floating device is arranged, in its direction downwards from the crest of a wave by means of the narrowing portion of the tubular body, to transport substantially the water contained in the tubular body. Which means, when the device, in a trough of a wave, returns to move upwards, that the water in the tubular body still flows downwards due to the kinetic energy of the water. By the fact that the tubular body at the bottom comprises an essentially larger cross section area than the narrowing portion in the vicinity of the opening, the water needs only to continue to stream downwards out of the tubular body a short distance for obtaining a heavy dropping of the level in the narrowing portion. Thereafter, a following pressure levelling leads to a rapid upwards directed water flow in the narrowing portion of the tubular body so that a water jet ejects upwards out of the opening. According to a test with a prototype, this water jet was obtained immediately before the floating device reaches a crest of a wave.
According to another preferred embodiment of the invention, the floating device comprises a weight body. By the weight of the weight body, the narrowing portion of the tubular body may transport the water contained in the tubular body downwards so that said level difference is established between the water contained in the tube and the surrounding water. The weight body also has the purpose to work as counterweight when the water is forced upwards through the narrowing portion. Said weight body may comprise a space, which is arranged to be filled with water. Thereby, a device is obtained with a considerable weight but the device itself does not need to be heavy. This is very favourable in view of the expenses. Suitably, said water-filled space may be provided externally around the narrowing portion. Thereby, a symmetrical downwards working weight is obtained, at the same time as the floating device may be constructed as a simply constructed symmetric unit. In order to prevent the water in said space from being filled over a suitable level, by e.g. ripples or rain, said space may comprise a passage, which allows a water flow between said space and the surrounding water. However, this passage is so small that the water level in the weight body does not immediately adapt to the level of the surrounding water. When the floating device is at crests and troughs of waves the water level of the weight body may be higher and lower, respectively, than the level of the surrounding water.
According to a further preferred embodiment of the invention, the floating device comprises floating elements, which are provided at the upper end of the tubular body. Thereby the elongated tubular body is kept floating in the water in an essentially vertical position. Preferably, in this case the floating element has a downwards directed conical shape so that the movement downwards of the floating device in a trough of a wave is not immediately slowed down but the device may Continue downwards in the water a short distance before it returns upwards by the next wave. Thereby, the water contained in the tubular body is also forced down said distance, whereby the desired level difference may be greater. A floating element located below its natural floating position moves rapidly upwards, which also favour the formation of said level difference. Consequently, the conical angle downwards of the floating body is very important for the function of the device.
According to an alternative embodiment of the invention, the device is anchored, wherein said level difference of the water in the tubular body and the surrounding water is established by the supply of air to the interior of tubular body. Such a construction of the device, where it is essentially stationary in relation to the surrounding water, may be suitable in calm waters and where a power source is available. In this case, e.g. a motor may drive a compressor, which via a conduit supplies air to the interior of the tubular body. When a sufficient quantity of water is pressed downwards by the supplied air, so that a sufficient pressure within the tubular body is obtained, said valve device will open, wherein an upwards directed water jet is obtained.
According to an advantageous embodiment of the invention, said narrowing portion of the tubular body comprises a conical shape. The narrowing portion may be shaped as a circular right-angled cone having a radius, which decreases continuously along a straight line until it ends in the opening, which is centrally located at the top of the tubular body. Another alternative is that the radius of the narrowing portion decreases along a curve, which is bent inwards against the centre of the narrowing portion. In this case, the radius may decrease progressively. By this shape of the narrowing portion, a higher water jet is generally formed than in the case with the narrowing portion, which is shaped as a circular right-angled cone.
According to another preferred embodiment of the invention a lighting device is provided on the device and directed so that it illuminates said water jet. By the fact that the water jet forms a relatively clear optical body the light from the lighting device will be spread in the whole water jet. This light effect will still attract further attention, whereby e.g. a ground may be observed and the distance estimated in a very good time, in this case, the lighting device may only be activated when said water jet ejects upwards. Another alternative may be that the lighting device is activated during determined intervals. It works usually since a water jet in any form is nearly the whole time present in the air. Thereby, the requirement of energy for the lighting device may be kept at a low level. In order to obtain energy to the lighting device, solar cells may be provided on the floating device. Thereby, the solar cells are arranged to generate electric energy, which is accumulated in batteries provided on a suitable place on the floating device.
According to another preferred embodiment, air or water flowing out from the opening may be arranged to drive a turbine for generating energy, Since the floating device in a very effective way transforms the kinetic energy of the waves to an upwards raising water level in the narrowing portion, the possibility to use the device for generating energy is offered.